We have evaluated the influence of age on kinetics of vancomycin in 12 healthy normal volunteers....6 young and 6 elderly, following a dose of 6mg/kg. Empiric modeling and parameter estimation revealed a significant prolongation in the mean elimination half-life of vancomycin in the elderly compared to the young (12.1 vs. 7.2 hrs.). Although initial dilution volume was the same in both groups, both systemic and renal clearance were significantly reduced in the elderly. Increase in Vss in the elderly was attributed to enhanced tissue binding of the drug which was estimated based on plasma protein binding and 40K - measurements. Indepth analysis of measurable excretion data tends to support previous claims of vancomycin elimination predominantly via glomerular filtration. Adjusting vancomycin dosage in the elderly to minimize potential for nephro - or otic toxicity is suggested.